At last sinxe july 1940 all Spitfire an dHurricane serving in combat squadrons in the south-east of UK should have CSP AFAIK.

CoD will have most propably two flyable Spifire Mk.I and Hurricane MkI.
My personal guss ia that the main difference between them will be the propellersystem.
I am also looking forward which propellersystem Maddox has choosen for the Bf109 & 110.